On 10/8/25 10:59, Roger Pau Monné wrote: > On Wed, Oct 08, 2025 at 04:39:23PM +0200, Roger Pau Monne wrote: >> I've had the luck to come across a PCI card that exposes a MSI-X capability >> where the BIR of the vector and PBA tables points at a BAR that has 0 size. >> >> This doesn't play nice with the code in vpci_make_msix_hole(), as it would >> still use the address of such empty BAR (0) and attempt to carve a hole in >> the p2m. This leads to errors like the one below being reported by Xen: >> >> d0v0 0000:22:00.0: existing mapping (mfn: 181c4300 type: 0) at 0 clobbers >> MSIX MMIO area >> >> And the device left unable to enable memory decoding due to the failure >> reported by vpci_make_msix_hole(). >> >> Introduce checking in init_msix() to ensure the BARs containing the MSI-X >> tables are usable. This requires checking that the BIR points to a >> non-empty BAR, and the offset and size of the MSI-X tables can fit in the >> target BAR. >> >> This fixes booting PVH dom0 on Supermicro AS -2126HS-TN severs with AMD >> EPYC 9965 processors. The broken device is: >> >> 22:00.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA >> Controller [AHCI mode] (rev 93) >> >> There are multiple of those integrated controllers in the system, all >> broken in the same way. >> >> Signed-off-by: Roger Pau Monné <[email protected]> >> Released-Acked-By: Oleksii Kurochko<[email protected]> >> --- >> Cc: Stewart Hildebrand <[email protected]> >> Cc: Oleksii Kurochko <[email protected]> >> --- >> Changes since v1: >> - Introduce a DEVICE BUG prefix. >> - Remove extra newline. >> - Fix typo in commit message. >> --- >> xen/drivers/vpci/msix.c | 50 ++++++++++++++++++++++++++++++++++++----- >> xen/include/xen/lib.h | 3 +++ >> 2 files changed, 48 insertions(+), 5 deletions(-) >> >> diff --git a/xen/drivers/vpci/msix.c b/xen/drivers/vpci/msix.c >> index 54a5070733aa..4ddcefbcb274 100644 >> --- a/xen/drivers/vpci/msix.c >> +++ b/xen/drivers/vpci/msix.c >> @@ -675,6 +675,51 @@ static int cf_check init_msix(struct pci_dev *pdev) >> if ( !msix ) >> return -ENOMEM; >> >> + msix->tables[VPCI_MSIX_TABLE] = >> + pci_conf_read32(pdev->sbdf, msix_table_offset_reg(msix_offset)); >> + msix->tables[VPCI_MSIX_PBA] = >> + pci_conf_read32(pdev->sbdf, msix_pba_offset_reg(msix_offset)); >> + >> + /* Check that the provided BAR is valid. */ > > I had the following local change that I forgot to update the patch > with before sending: > > /* Check that the referenced BAR(s) regions are valid. */ > > I think this is a better wording.
+1
